Yesterday, the Buffalo wireless cable router and the Virgin Media installers all turned up in good time, so I'm writing this via a faster (2Mb) internet connection and using quite different hardware than before.
Everything is now working well but the broadband installation was less than straightforward because of some little things that Virgin didn't do - like create an internet account for me!
I've done a blog about the experience, which you may care to read:
Bob gets Virgin Media broadband & TV but is less than impressed with the installation